Welding material for copper-nickel gradient structure low heat input CMT preparation, copper-nickel gradient structure and method

Abstract

The invention discloses a welding material for copper-nickel gradient structure low heat input CMT preparation. The welding material comprises a near-copper layer welding material and a near-nickel layer welding material. The near-copper layer welding material comprises powder and a welding skin, and the powder comprises, by mass, 40.0%-50.0% of Ni powder, 10.0%-20.0% of Zn powder, 5.0%-10.0% of Si powder, 5.0%-10.0% of Sn powder and the balance Cu powder. The near-nickel layer welding material comprises powder and a welding skin, and the powder comprises, by mass, 40.0%-50.0% of Cu powder, 10.0%-20.0% of Ag powder, 10.0%-20.0% of Zn powder and the balance Ni powder. The material is used for solving the problems that a copper-nickel gradient structure prepared through an existing method has pores and is not fused. The invention further discloses a low-heat-input CMT preparation method of the copper-nickel gradient structure and the copper-nickel gradient structure.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of metal materials, and particularly relates to a welding material for preparing a copper-nickel gradient structure low-heat-input CMT, and further relates to a method for preparing a copper-nickel gradient structure low-heat-input CMT and a copper-nickel gradient structure. BACKGROUND

[0002] With the rapid development of high-end manufacturing fields such as aerospace, nuclear power engineering and microelectronic packaging, the comprehensive performance of key components under complex working conditions is put forward with extremely high requirements. For example, in some components, one end needs to have excellent electrical conductivity and thermal conductivity like copper, and the other end needs to have high temperature strength, oxidation resistance and corrosion resistance like nickel. A single homogeneous material cannot meet the harsh demand of integrating multiple properties in the same component.

[0003] To solve this problem, copper-nickel gradient functional materials have emerged. Through the continuous and smooth change of the composition and structure in space, the performance of the material is gradually transitioned, which can effectively alleviate the stress concentration problem caused by the mismatch of physical properties (such as thermal expansion coefficient and thermal conductivity) at the junction of dissimilar materials, thereby improving the reliability and service life of the component.

[0004] At present, the common methods for preparing copper-nickel gradient structure include powder metallurgy, laser cladding and thermal spraying. However, these methods still face many challenges in practical application. The powder metallurgy method is complex, has a long preparation period, and is difficult to manufacture dense components of large size or complex shape; although laser cladding and thermal spraying technology are flexible, they are prone to introduce defects such as pores and incomplete fusion, and have extremely high requirements for equipment and process control. The more core technical difficulty lies in the physical and metallurgical properties of copper and nickel. First, copper has a very high thermal conductivity, and during welding or cladding, heat will quickly dissipate from the heating zone, resulting in an unstable molten pool and making it difficult to form a good metallurgical bond. Second, although copper and nickel can form an infinite solid solution in the equilibrium state, in the non-equilibrium rapid solidification process (such as most additive manufacturing or welding processes), it is easy to precipitate metastable phases such as Cu-Ni brittle intermetallic compounds. The existence of these brittle phases will seriously deteriorate the mechanical properties of the interface region, making the gradient layer become the source of crack initiation and propagation under stress, leading to premature failure of the structure.

[0005] Therefore, developing a special welding material and method that can effectively connect copper and nickel and achieve smooth transition of performance is the key to breaking through the bottleneck of engineering application of copper-nickel gradient structure. SUMMARY

[0006] The first object of the present application is to provide a copper-nickel gradient structure low heat input CMT preparation welding material to solve the problem of pores and incomplete fusion in the copper-nickel gradient structure prepared by the existing method.

[0007] The second object of the present application is to provide a copper-nickel gradient structure low heat input CMT preparation method.

[0008] The third object of the present application is to provide a copper-nickel gradient structure.

[0009] The first technical solution adopted by the present application is a copper-nickel gradient structure low heat input CMT preparation welding material, which comprises a near-copper layer welding material and a near-nickel layer welding material. The near-copper layer welding material comprises a powder and a welding skin, wherein the powder comprises the following components in mass percentage: Ni powder 40.0-50.0%, Zn powder 10.0-20.0%, Si powder 5.0-10.0%, Sn powder 5.0-10.0%, and the balance being Cu powder, and the sum of the mass percentages of the above components is 100%. The near-nickel layer welding material comprises a powder and a welding skin, wherein the powder comprises the following components in mass percentage: Cu powder 40.0-50.0%, Ag powder 10.0-20.0%, Zn powder 10.0-20.0%, and the balance being Ni powder, and the sum of the mass percentages of the above components is 100%.

[0010] The purity of each raw material powder constituting the near-copper layer welding material and the near-nickel layer welding material is ≥99.9%.

[0011] The particle size of each raw material powder constituting the near-copper layer welding material and the near-nickel layer welding material is 100-200 mesh.

[0012] The present application is further characterized in that: The welding skin of the near-copper layer welding material is a pure copper strip with a thickness of 0.4 mm and a width of 7 mm. The filling rate of the near-copper layer welding material is controlled to be 25-30 wt%.

[0013] The welding skin of the near-nickel layer welding material is a pure nickel strip with a thickness of 0.4 mm and a width of 7 mm. The filling rate of the near-nickel layer welding material is controlled to be 20-25 wt%.

[0014] The preparation method of the near-copper layer welding material is as follows: Step 1: weigh the Ni powder 40.0-50.0%, the Zn powder 10.0-20.0%, the Si powder 5.0-10.0%, the Sn powder 5.0-10.0%, and the balance being Cu powder, in mass percentage, and the sum of the mass percentages of the above components is 100%. Step 2: The medicine powder weighed in step 1 is heated in a vacuum heating furnace, the heating temperature is 200-240 DEG C, the holding time is 1-2 hours, and the crystal water in the medicine powder is removed; the dried medicine powder is placed in a powder mixer for sufficient mixing, and the mixing time is 1-2 hours; Step 3: A pure copper strip is used as a welding skin, alcohol is used to remove grease on the surface of the pure copper strip, the medicine powder prepared in step 2 is wrapped in the pure copper strip through a cored wire drawing equipment, and the first drawing die has a hole diameter of 2.6 mm; In step 3, the filling rate of the cored wire is controlled to be 25-30 wt%; the thickness of the pure copper strip is 0.4 mm, and the width is 7 mm; Step 4: After the first process of drawing is completed, the die hole diameter is sequentially reduced, and finally the cored wire with a diameter of 1.2 mm is obtained; Step 5: After the cored wire drawing is completed, the cored wire is wound on a welding wire disc through a winding machine, and finally sealed in a cored wire vacuum packaging bag for use.

[0015] The preparation method of the near-nickel layer welding material is as follows: Step 1: Cu powder 40.0-50.0%, Ag powder 10.0-20.0%, Zn powder 10.0-20.0%, and the rest is Ni powder are weighed according to the mass percentage, and the sum of the mass percentages of the above components is 100%; Step 2: The medicine powder weighed in step 1 is heated in a vacuum heating furnace, the heating temperature is 220-260 DEG C, the holding time is 1-2 hours, and the crystal water in the medicine powder is removed; the dried medicine powder is placed in a powder mixer for sufficient mixing, and the mixing time is 1-2 hours; Step 3: A pure nickel strip is used as a welding skin, alcohol is used to remove grease on the surface of the pure nickel strip, the medicine powder prepared in step 2 is wrapped in the pure nickel strip through a cored wire drawing equipment, and the first drawing die has a hole diameter of 2.6 mm; In step 3, the filling rate of the cored wire is controlled to be 20-25 wt%; the thickness of the pure copper strip is 0.4 mm, and the width is 7 mm; Step 4: After the first process of drawing is completed, the die hole diameter is sequentially reduced, and finally the cored wire with a diameter of 1.2 mm is obtained; Step 5: After the cored wire drawing is completed, the cored wire is wound on a welding wire disc through a winding machine, and finally sealed in a cored wire vacuum packaging bag for use.

[0016] The second technical scheme adopted by the application is a low heat input CMT preparation method of a copper-nickel gradient structure, and the specific steps are as follows: Step 1, the near copper layer welding material is selected, and a CMT arc welding process is used to prepare a near copper layer on a copper base; Step 2, the near-nickel layer welding material is selected, and the near-nickel layer is prepared on the near-copper layer weld prepared in step 1 by adopting the CMT arc surfacing process; Step 3, the ERNi-1 pure nickel welding wire is adopted to perform the CMT arc surfacing on the near-nickel layer prepared in step 2 to prepare the nickel layer. The application is also characterized in that: In step 1, the CMT welding current is 250A~300A, and the surfacing layer thickness is 2mm~4mm; In step 2, the CMT welding current is 160A~200A, and the surfacing layer thickness is 2mm~4mm; In step 3, the CMT welding current is 180~250A, and the surfacing layer thickness is 10mm~15mm.

[0017] The third technical solution adopted by the application is a copper-nickel gradient structure prepared by the above method.

[0018] The application has the following beneficial effects: (1) The method of the application adopts the CMT arc method to prepare the copper-nickel gradient structure, compared with the laser cladding and spraying methods, the gradient structure prepared has a larger size, is more compact inside, has better quality, and has higher popularization and application value.

[0019] (2) The method of the application is aimed at the welding characteristics of nickel and copper, in order to avoid the generation of brittle phases in the welding non-equilibrium process, the transition layer is prepared in the near-copper layer and the near-nickel layer respectively, and the obtained gradient structure has high strength and good toughness.

[0020] (3) The near-copper layer welding material of the application is mainly copper-based alloy, and Ni, Zn, Si, Sn and other elements are added, which effectively improves the melting point of the near-copper layer and the bonding performance with the copper substrate through the synergistic effect of multiple elements.

[0021] (4) The near-nickel layer welding material of the application is mainly nickel-based alloy, and Cu, Ag, Zn powder is added, which effectively ensures the metallurgical bonding with the near-copper layer weld and the bonding with the nickel-based structure.

[0022] (5) The welding wire of the application can be used for TIG welding and MIG welding, and has high popularization value.

[0023] (6) The copper-nickel gradient structure low heat input CMT preparation welding material of the application can form firm and tough metallurgical bonding with copper and nickel at the same time, the physical and chemical properties thereof can bridge the performance difference between the two base materials, and through reasonable process design, the generation of brittle phases is inhibited, and finally the copper-nickel gradient structure with continuous composition change, dense structure and excellent performance is obtained. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 Flow chart for the low heat input CMT preparation method of the copper-nickel gradient structure of the present application; Figure 2 Microstructure of the near copper layer surfacing layer in the copper-nickel gradient structure prepared using Example 2; Figure 3 Microstructure of the near nickel layer surfacing layer in the copper-nickel gradient structure prepared using Example 2; Figure 4 Tensile fracture scanning electron microscope observation morphology of the copper-nickel gradient structure prepared in Example 2. DETAILED DESCRIPTION

[0025] The present application will be described in detail below in conjunction with the drawings and specific embodiments.

[0026] The present application provides a copper-nickel gradient structure low heat input CMT preparation welding material, including a near copper layer welding material and a near nickel layer welding material; The near copper layer welding material includes a flux powder and a welding skin, wherein the flux powder includes the following components in mass percentage: Ni powder 40.0-50.0%, Zn powder 10.0-20.0%, Si powder 5.0-10.0%, Sn powder 5.0-10.0%, and the balance being Cu powder, and the sum of the mass percentages of the above components is 100%. The purity of each raw material component alloy powder of the near copper layer welding material is ≥99.9%.

[0027] The particle size of the flux powder for the near copper layer welding material is 100-200 mesh.

[0028] The welding skin of the near copper layer welding material is a pure copper strip with a thickness of 0.4 mm and a width of 7 mm.

[0029] The filling rate of the near copper layer welding material is controlled at 25wt%-30wt%.

[0030] The near nickel layer welding material includes a flux powder and a welding skin, wherein the flux powder includes the following components in mass percentage: Cu powder 40.0-50.0%, Ag powder 10.0-20.0%, Zn powder 10.0-20.0%, and the balance being Ni powder, and the sum of the mass percentages of the above components is 100%.

[0031] The purity of each raw material component alloy powder of the near nickel layer welding material is ≥99.9%.

[0032] The particle size of the flux powder for the near nickel layer welding material is 100-200 mesh.

[0033] The welding skin of the near nickel layer welding material is a pure nickel strip with a thickness of 0.4 mm and a width of 7 mm.

[0034] The filling rate of the near-nickel layer welding material is controlled at 20wt%~25wt%.

[0035] The roles and functions of the main components in the near-copper layer welding material and the near-nickel layer welding material are as follows: (1) The main elements of the near-copper layer welding material are: Cu, Ni, Zn, Si, and Sn.

[0036] 1) Cu element: The near-copper layer welding material is used for welding on a copper substrate, so the welding material mainly contains Cu to ensure excellent welding metallurgical bonding performance.

[0037] 2) Ni element: According to the Cu-Ni binary phase diagram, Ni can be solid-solved in Cu, and the subsequent near-nickel layer mainly contains Ni, so adding Ni element in the near-copper layer can ensure the welding bonding strength with the subsequent surfacing layer weld. The addition of Ni can improve the strength of Cu and form a solid solution structure.

[0038] 3) Zn element: According to the Cu-Zn binary phase diagram, the maximum solid solubility of Zn in Cu is 38.95w.t%, so the added Zn cannot exceed the above content. Zn solid-solved in Cu can effectively improve the strength of the copper-based surfacing layer, and because of the low melting point of Zn, the melting point of the welding material can be significantly reduced, thereby reducing the heat input.

[0039] 4) Si element: Si atoms can be solid-solved in the copper lattice, causing lattice distortion, thereby significantly hindering dislocation movement and improving the strength and hardness of the alloy. A small amount of silicon (1%~3%) can greatly improve the strength of copper while still maintaining good plasticity.

[0040] 5) Sn element: The maximum solid solubility of Sn in Cu is 15.8%. The solid solution of Sn can improve the strength of Cu and significantly reduce its melting point, thereby reducing the welding heat input. The addition of Sn can also significantly improve the corrosion resistance of copper-based alloys.

[0041] (2) The main elements of the near-nickel layer welding material are: Ni, Cu, Ag, and Zn.

[0042] 1) Ni element: The near-nickel layer is used for surfacing with nickel-based welding wire, which is to prepare a nickel-based structure. Therefore, the near-nickel layer mainly contains Ni to ensure excellent welding bonding performance with the nickel-based surfacing layer above. The near-nickel layer is welded on the near-copper layer, and Ni and Cu have excellent weldability, so the near-nickel layer mainly contains Ni element, which also ensures the welding bonding performance with the bottom near-copper layer.

[0043] 2) Cu element: according to the excellent welding performance of Cu and Ni, adding Cu in the near-nickel layer welding material can also significantly improve the strength of the nickel-based cladding layer. And since the near-copper layer is also dominated by Cu element, the addition of Cu in the near-nickel layer ensures the connection strength and welding forming with the bottom near-copper layer.

[0044] 3) Ag element: according to the Ag-Ni binary phase diagram, the amount of Ag that can be dissolved in Ni is only 1.8wt.%, but Ag and Cu are infinitely soluble, so the added Ag preferentially dissolves in Cu and then in Ni, thereby significantly improving the strength of the near-nickel layer cladding layer. The melting point of Ag is relatively low, and the addition of Ag can significantly reduce the welding heat input of the near-nickel layer.

[0045] 4) Zn element: a small amount of Zn dissolved in the Ni matrix can significantly improve the strength of Ni. The melting point of Zn is relatively low, which can significantly reduce the heat input during welding of the near-nickel layer and avoid damage to the near-copper layer.

[0046] The preparation method of the near-copper layer welding material includes the following specific steps: Step 1: respectively take Ni powder 40.0-50.0%, Zn powder 10.0-20.0%, Si powder 5.0-10.0%, Sn powder 5.0-10.0%, and the balance is Cu powder, according to the mass percentage, the sum of the mass percentages of the above components is 100%; Step 2: place the powder prepared in step 1 in a vacuum heating furnace and heat it, the heating temperature is 200-240℃, and the holding time is 1-2h, to remove the crystal water in the powder; after drying, the powder is placed in a powder mixer for thorough mixing, and the mixing time is 1-2h; Step 3: use pure copper tape as the welding skin, use alcohol to remove the grease on the surface of the pure copper tape, and wrap the powder prepared in step 2 in the pure copper tape through the core wire drawing equipment, and the first drawing die hole diameter is 2.6mm; In step 3, the filling rate of the flux-cored wire is controlled at 25-30wt%; the thickness of the pure copper tape is 0.4mm, and the width is 7mm; Step 4: after the first process drawing is completed, the die hole diameter is gradually reduced, and finally a diameter of 1.2mm of the flux-cored wire is obtained; Step 5: after the drawing of the flux-cored wire is completed, it is wound on the welding wire disc through the winding machine, and finally sealed in the vacuum packaging bag of the flux-cored wire for use.

[0047] The preparation method of the near-nickel layer welding material includes the following specific steps: Step 1: Cu powder 40.0~50.0%, Ag powder 10.0~20.0%, Zn powder 10.0~20.0%, and the rest is Ni powder are weighed according to the mass percentage, and the sum of the mass percentages of the above components is 100%; Step 2: The powder weighed in step 1 is placed in a vacuum heating furnace for heating, the heating temperature is 220℃~260℃, and the holding time is 1h~2h to remove the crystal water in the powder; the dried powder is placed in a powder mixer for thorough mixing, and the mixing time is 1h~2h; Step 3: pure nickel tape is used as the welding skin, alcohol is used to remove the grease on the surface of the pure nickel tape, the powder prepared in step 2 is wrapped in the pure nickel tape through the core wire drawing equipment, and the first drawing die hole diameter is 2.6mm; In step 3, the filling rate of the flux-cored wire is controlled at 20wt%~25wt%; the thickness of the pure nickel tape is 0.4mm, and the width is 7mm; Step 4: After the first process of drawing is completed, the die hole diameter is gradually reduced, and finally the flux-cored wire with a diameter of 1.2mm is obtained; Step 5: After the drawing of the flux-cored wire is completed, it is wound on the welding wire disc through the winding machine, and finally sealed in the vacuum packaging bag of the flux-cored wire for use.

[0048] The application also provides a low heat input CMT preparation method of copper-nickel gradient structure, which uses the prepared near copper layer welding material and near nickel layer welding material to prepare the copper-nickel gradient structure low heat input CMT, and the specific steps are as follows (as shown in Figure 1 Step 1: select the above-mentioned near copper layer welding material, and use the CMT arc welding process to prepare the near copper layer on the copper substrate; In step 1, the CMT welding current is 250A~300A, and the thickness of the surfacing layer is 2mm~4mm; Step 2: select the above-mentioned near nickel layer welding material, and use the CMT arc welding process to prepare the near nickel layer on the near copper layer prepared in step 1; In step 2, the CMT welding current is 160A~200A, and the thickness of the surfacing layer is 2mm~4mm; Step 3: use ERNi-1 pure nickel welding wire to perform CMT arc welding on the near nickel layer prepared in step 2 to prepare a nickel layer. In step 3, the CMT welding current is 180~250A, and the thickness of the surfacing layer is 10mm~15mm.

[0049] The application also provides a copper-nickel gradient structure, which is prepared by the above method and comprises a copper substrate, a near copper layer, a near nickel layer and a nickel layer arranged from top to bottom.

[0050] Example 1​ The preparation method of the near-copper layer welding material is as follows: Step 1: the mass percentage of each component is as follows: Ni powder 40.0%, Zn powder 10.0%, Si powder 5.0%, Sn powder 5.0%, and the balance is Cu powder; the sum of the mass percentages of the above components is 100%; The purity of each raw material component alloy powder of the near-copper layer welding material is ≥99.9%.

[0051] The particle size of the powder for the near-copper layer welding material is 100 mesh.

[0052] Step 2: the powder weighed in step 1 is heated in a vacuum heating furnace, the heating temperature is 200°C, and the holding time is 1h, to remove the crystal water in the powder; the dried powder is placed in a powder mixer for thorough mixing, and the mixing time is 1h; Step 3: pure copper tape is used as the welding skin, alcohol is used to remove the grease on the surface of the pure copper tape, the powder prepared in step 2 is wrapped in the pure copper tape through a flux-cored wire drawing equipment, and the hole diameter of the first drawing die is 2.6mm; In step 3, the filling rate of the flux-cored wire is controlled at 25wt%; the thickness of the pure copper tape is 0.4mm, and the width is 7mm.

[0053] Step 4: after the first process of drawing is completed, the die hole diameter is gradually reduced, and finally the flux-cored wire with a diameter of 1.2mm is obtained.

[0054] Step 5: after the drawing of the flux-cored wire is completed, the wire is wound on a wire spool through a winding machine, and finally sealed in a vacuum packaging bag for the flux-cored wire for use.

[0055] The preparation method of the near-copper layer welding material is as follows: Step 1: the mass percentage of each component is as follows: Cu powder 40.0%, Ag powder 10.0%, Zn powder 10.0%, and the balance is Ni powder; the sum of the mass percentages of the above components is 100%; The purity of each raw material component alloy powder of the near-copper layer welding material is ≥99.9%.

[0056] The particle size of the powder for the near-copper layer welding material is 100 mesh.

[0057] Step 2: the powder weighed in step 1 is heated in a vacuum heating furnace, the heating temperature is 220°C, and the holding time is 1h, to remove the crystal water in the powder; the dried powder is placed in a powder mixer for thorough mixing, and the mixing time is 1h; Step 3: pure copper tape is used as the welding skin, alcohol is used to remove the grease on the surface of the pure copper tape, the powder prepared in step 2 is wrapped in the pure copper tape through a flux-cored wire drawing equipment, and the hole diameter of the first drawing die is 2.6mm; In step 3, the filling rate of the flux-cored wire is controlled at 20wt%; the thickness of the pure nickel strip is 0.4mm, and the width is 7mm.

[0058] Step 4: After the first process drawing is completed, the hole diameter of the mold is sequentially reduced, and finally the flux-cored wire with a diameter of 1.2mm is obtained.

[0059] Step 5: After the drawing of the flux-cored wire is completed, it is wound on the welding wire disc by the winding machine, and finally sealed in the vacuum packaging bag of the flux-cored wire for use.

[0060] The near-copper layer welding material and the near-nickel layer welding material prepared in Example 1 are used to prepare a copper-nickel gradient structure by low heat input CMT. The specific steps are as follows (as shown in Figure 1 ): Step 1: Select the above-mentioned near-copper layer welding material, and use CMT arc welding process to prepare the near-copper layer on the copper base; the CMT welding current is 250A, and the thickness of the deposited layer is 2mm; Step 2: Select the above-mentioned near-nickel layer welding material, and use CMT arc welding process to prepare the near-nickel layer on the near-copper layer prepared in step 1; the CMT welding current is 160A, and the thickness of the deposited layer is 2mm.

[0061] Step 3: Use ERNi-1 pure nickel welding wire to prepare a nickel layer on the near-nickel layer prepared in step 2 by CMT arc welding; the welding current is 180A, and the thickness of the deposited layer is 10mm.

[0062] After testing, the tensile strength of the copper-nickel gradient structure is 283MPa.

[0063] Example 2 The specific steps of the preparation method of the near-copper layer welding material are as follows: Step 1: The Ni powder, Zn powder, Si powder, Sn powder and Cu powder are weighed according to the mass percentage of 50.0%, 20.0%, 10.0%, 10.0% and the balance, respectively; the sum of the mass percentages of the above components is 100%. The purity of each raw material component alloy powder of the above-mentioned near-nickel layer welding material is ≥99.9%.

[0064] The particle size of the powder for the near-nickel layer welding material is 200 mesh.

[0065] Step 2: Put the powder weighed in step 1 into a vacuum heating furnace and heat it, the heating temperature is 240℃, and the holding time is 2h, to remove the crystal water in the powder; after drying, the powder is placed in a powder mixer for thorough mixing, and the mixing time is 2h. Step 3: Using pure copper strip as the solder coating, use alcohol to remove the grease from the surface of the pure copper strip, and wrap the flux powder prepared in step 2 inside the pure copper strip using a flux-cored wire drawing device. The diameter of the first drawing die is 2.6mm. In step 3, the filler content of the flux-cored wire is controlled at 30wt%; the thickness of the pure copper strip is 0.4mm and the width is 7mm.

[0066] Step 4: After the first drawing process is completed, the die hole diameter is reduced in sequence to finally obtain a flux-cored wire with a diameter of 1.2mm.

[0067] Step 5: After the flux-cored welding wire is drawn, it is wound onto the welding wire spool by a wire winding machine and finally sealed in a flux-cored welding wire vacuum packaging bag for later use.

[0068] The specific steps for preparing near-nickel layer welding materials are as follows: Step 1: Weigh out 50.0% Cu powder, 20.0% Ag powder, and 20.0% Zn powder by mass percentage, with the remainder being Ni powder. The sum of the mass percentages of the above components is 100%. Step 2: Place the powder weighed in Step 1 into a vacuum heating furnace and heat it at 260℃ for 2 hours to remove the water of crystallization from the powder; place the dried powder into a powder mixer for thorough mixing for 2 hours. Step 3: Using pure nickel strip as the solder coating, use alcohol to remove the grease from the surface of the pure nickel strip, and wrap the flux powder prepared in step 2 inside the pure nickel strip using a flux-cored wire drawing device. The diameter of the first drawing die is 2.6mm. In step 3, the filler content of the flux-cored wire is controlled at 25 wt%; the pure nickel strip has a thickness of 0.4 mm and a width of 7 mm.

[0069] Step 4: After the first drawing process is completed, the die hole diameter is reduced in sequence to finally obtain a flux-cored wire with a diameter of 1.2mm.

[0070] Step 5: After the flux-cored welding wire is drawn, it is wound onto the welding wire spool by a wire winding machine and finally sealed in a flux-cored welding wire vacuum packaging bag for later use.

[0071] The copper-nickel gradient CMT with low heat input was fabricated using the near-copper layer solder material and near-nickel layer solder material prepared in Example 2. The specific steps of the fabrication method for the copper-nickel gradient CMT with low heat input are as follows (e.g.) Figure 1 (as shown) Step 1: Select the above-mentioned near-copper layer welding material and use CMT arc welding process to prepare a near-copper layer on the copper substrate. The CMT welding current is 300A and the thickness of the weld layer is 4mm. Step 2: Selecting the near-nickel layer welding material as described above, a near-nickel layer is prepared on the near-copper layer welding seam prepared in Step 1 by using the CMT arc surfacing process; the CMT welding current is 200 A, and the surfacing layer thickness is 4 mm.

[0072] Step 3: A nickel layer is prepared on the near-nickel layer prepared in Step 2 by using the ERNi-1 pure nickel welding wire to perform CMT arc surfacing, the welding current is 250 A, and the surfacing layer thickness is 15 mm.

[0073] After testing, the tensile strength of the copper-nickel gradient structure is 288 MPa.

[0074] Figure 2 The microstructure of the near-copper layer surfacing layer in the copper-nickel gradient structure prepared in Example 2 is shown in the figure. As can be seen from the figure, the microstructure of the near-copper layer surfacing layer is mainly copper-based solid solution, and no pores and cracks are found.

[0075] Figure 3 The microstructure of the near-nickel layer surfacing layer in the copper-nickel gradient structure prepared in Example 2 is shown in the figure. As can be seen from the figure, the microstructure of the near-nickel layer surfacing layer is mainly nickel-based solid solution, and no pores and cracks are found.

[0076] Figure 4 The scanning electron microscope observation morphology of the tensile fracture of the copper-nickel gradient structure prepared in Example 2 is shown in the figure. As can be seen from the figure, the fracture surface is mainly ductile dimples, and the toughness is good.

[0077] Example 3 The preparation method of the near-copper layer welding material is as follows: Step 1: The Ni powder is 45.0%, the Zn powder is 15.0%, the Si powder is 7.0%, the Sn powder is 7.0%, and the balance is Cu powder, and the sum of the mass percentages of the above components is 100%. The purity of each raw material component alloy powder of the near-nickel layer welding material is ≥99.9%.

[0078] The particle size of the flux powder for the near-nickel layer welding material is 200 mesh.

[0079] Step 2: The flux powder weighed in Step 1 is placed in a vacuum heating furnace for heating, the heating temperature is 220°C, and the holding time is 1.5 h to remove the crystal water in the flux powder; the dried flux powder is placed in a powder mixer for thorough mixing, and the mixing time is 1.5 h; Step 3: A pure copper strip is used as the welding strip, alcohol is used to remove the grease on the surface of the pure copper strip, the flux powder prepared in Step 2 is wrapped in the pure copper strip by using a flux cored wire drawing equipment, and the first drawing die hole diameter is 2.6 mm. In step 3, the filling rate of the flux-cored wire is controlled at 28wt%; the thickness of the pure copper strip is 0.4mm, and the width is 7mm.

[0080] In step 4, after the first process of drawing is completed, the hole diameter of the die is sequentially reduced, and finally the flux-cored wire with a diameter of 1.2mm is obtained.

[0081] In step 5, after the drawing of the flux-cored wire is completed, the wire is wound on the wire spool by the winding machine, and finally sealed in the vacuum packaging bag of the flux-cored wire for use.

[0082] The preparation method of the near-nickel layer welding material is as follows: In step 1, Cu powder 45.0%, Ag powder 15.0%, Zn powder 15.0%, and the rest Ni powder are weighed according to the mass percentage, and the sum of the mass percentages of the above components is 100%; The purity of each raw material component alloy powder of the near-nickel layer welding material is ≥99.9%.

[0083] The particle size of the powder for the near-nickel layer welding material is 200 mesh.

[0084] In step 2, the powder weighed in step 1 is heated in a vacuum heating furnace, the heating temperature is 240℃, the holding time is 1.5h, and the crystal water in the powder is removed; the dried powder is placed in a powder mixer for thorough mixing, and the mixing time is 1.5h; In step 3, pure nickel strip is used as the welding skin, alcohol is used to remove the grease on the surface of the pure nickel strip, the powder prepared in step 2 is wrapped in the pure nickel strip by the flux-cored wire drawing equipment, and the hole diameter of the first drawing die is 2.6mm. In step 3, the filling rate of the flux-cored wire is controlled at 22wt%; the thickness of the pure nickel strip is 0.4mm, and the width is 7mm.

[0085] In step 4, after the first process of drawing is completed, the hole diameter of the die is sequentially reduced, and finally the flux-cored wire with a diameter of 1.2mm is obtained.

[0086] In step 5, after the drawing of the flux-cored wire is completed, the wire is wound on the wire spool by the winding machine, and finally sealed in the vacuum packaging bag of the flux-cored wire for use.

[0087] The near-copper layer welding material and the near-nickel layer welding material prepared in Example 3 are used to prepare a copper-nickel gradient structure low heat input CMT, and the preparation method of the copper-nickel gradient structure low heat input CMT is as follows (as shown in Figure 1 ): In step 1, the near-copper layer welding material is selected, and a near-copper layer is prepared on a copper substrate by using a CMT arc welding process, the CMT welding current is 270A, and the thickness of the cladding layer is 3mm. Step 2, selecting the near-nickel layer welding material described above, using CMT arc surfacing process to prepare the near-nickel layer on the near-copper layer weld prepared in step 1; the CMT welding current is 180A, and the surfacing layer thickness is 3mm.

[0088] Step 3, using ERNi-1 pure nickel welding wire to perform CMT arc surfacing on the near-nickel layer prepared in step 2 to prepare a nickel layer, the welding current is 215A, and the surfacing layer thickness is 13mm.

[0089] Through testing, the tensile strength of the copper-nickel gradient structure is 298MPa.

[0090] Example 4 The preparation method of the near-copper layer welding material is as follows: Step 1: weighing the Ni powder 41.0%, the Zn powder 11.0%, the Si powder 6.0%, the Sn powder 6.0%, and the balance of the Cu powder according to the mass percentage, and the sum of the mass percentages of the above components is 100%; The purity of each raw material component alloy powder of the near-nickel layer welding material described above is ≥99.9%.

[0091] The particle size of the flux powder for the near-nickel layer welding material is 100 mesh.

[0092] Step 2: placing the flux powder weighed in step 1 in a vacuum heating furnace for heating, the heating temperature is 210℃, and the holding time is 1.2h to remove the crystal water in the flux powder; placing the dried flux powder in a powder mixer for thorough mixing, and the mixing time is 1.2h; Step 3: using pure copper tape as the welding skin, using alcohol to remove the grease on the surface of the pure copper tape, wrapping the flux powder prepared in step 2 in the pure copper tape through the flux-cored wire drawing equipment, and the first drawing die hole diameter is 2.6mm. In step 3, the filling rate of the flux-cored wire is controlled at 26wt%; the thickness of the pure copper tape is 0.4mm, and the width is 7mm.

[0093] Step 4: after the first process drawing is completed, the die hole diameter is sequentially reduced, and finally the flux-cored wire with a diameter of 1.2mm is obtained.

[0094] Step 5: after the flux-cored wire drawing is completed, winding the flux-cored wire on the welding wire disc through the winding machine, and finally sealing the flux-cored wire in the vacuum packaging bag for use.

[0095] The preparation method of the near-nickel layer welding material is as follows: Step 1: weighing the Cu powder 41.0%, the Ag powder 11.0%, the Zn powder 11.0%, and the balance of the Ni powder according to the mass percentage, and the sum of the mass percentages of the above components is 100%; The purity of each raw material component alloy powder of the near-nickel layer welding material is ≥99.9%.

[0096] The particle size of the flux powder for the near-nickel layer welding material is 150 mesh.

[0097] Step 2: The weighed flux powder in step 1 is heated in a vacuum heating furnace, the heating temperature is 230°C, and the holding time is 1.2h to remove the crystal water in the flux powder; the dried flux powder is placed in a powder mixer for thorough mixing, and the mixing time is 1.2h. Step 3: A pure nickel strip is used as the welding skin, alcohol is used to remove the grease on the surface of the pure nickel strip, the flux powder prepared in step 2 is wrapped in the pure nickel strip through a flux-cored wire drawing equipment, and the first drawing die hole diameter is 2.6mm. In step 3, the filling rate of the flux-cored wire is controlled at 22wt%; the thickness of the pure nickel strip is 0.4mm, and the width is 7mm.

[0098] Step 4: After the first process of drawing is completed, the die hole diameter is gradually reduced, and finally the flux-cored wire with a diameter of 1.2mm is obtained.

[0099] Step 5: After the drawing of the flux-cored wire is completed, the flux-cored wire is wound on a welding wire disc through a wire winding machine, and finally sealed in a vacuum packaging bag for use.

[0100] The near-copper layer welding material and the near-nickel layer welding material prepared in Example 4 are used to prepare a copper-nickel gradient structure by low heat input CMT, and the specific steps are as follows (as shown in Figure 1 ). Step 1: Select the near-copper layer welding material described above, and use the CMT arc welding process to prepare the near-copper layer on the copper substrate, the CMT welding current is 251A, and the thickness of the deposited layer is 2.4mm. Step 2: Select the near-nickel layer welding material described above, and use the CMT arc welding process to prepare the near-nickel layer on the near-copper layer weld prepared in step 1; the CMT welding current is 161A, and the thickness of the deposited layer is 2.4mm.

[0101] Step 3: Use ERNi-1 pure nickel welding wire to prepare a nickel layer on the near-nickel layer prepared in step 2 by CMT arc welding, the welding current is 181A, and the thickness of the deposited layer is 11mm.

[0102] After testing, the tensile strength of the copper-nickel gradient structure is 280MPa.

[0103] Example 5 The specific steps of the preparation method of the near-copper layer welding material are as follows: Step 1: weigh the powders according to the mass percentage, respectively, 42.0% of Ni powder, 12.0% of Zn powder, 5.2% of Si powder, 5.2% of Sn powder, and the rest of Cu powder, and the sum of the mass percentages of the above components is 100%; The purity of each raw material component alloy powder of the near-nickel layer welding material is ≥99.9%.

[0104] The particle size of the powder for the near-nickel layer welding material is 100 mesh.

[0105] Step 2: place the powder weighed in step 1 in a vacuum heating furnace and heat it, the heating temperature is 220℃, and the holding time is 1.1h, to remove the crystal water in the powder; place the dried powder in a powder mixer for thorough mixing, and the mixing time is 1.1h; Step 3: use pure copper tape as the welding skin, use alcohol to remove the grease on the surface of the pure copper tape, wrap the powder prepared in step 2 in the pure copper tape through the powder core welding wire drawing equipment, and the first drawing die hole diameter is 2.6mm; In step 3, the filling rate of the powder core welding wire is controlled at 27wt%; the thickness of the pure copper tape is 0.4mm, and the width is 7mm.

[0106] Step 4: after the first process drawing is completed, the die hole diameter is gradually reduced, and finally the powder core welding wire with a diameter of 1.2mm is obtained.

[0107] Step 5: after the powder core welding wire drawing is completed, it is wound on the welding wire disc through the winding machine, and finally sealed in the powder core welding wire vacuum packaging bag for use.

[0108] The preparation method of the near-nickel layer welding material is as follows: Step 1: weigh the powders according to the mass percentage, respectively, 42.0% of Cu powder, 12.0% of Ag powder, 12.0% of Zn powder, and the rest of Ni powder, and the sum of the mass percentages of the above components is 100%; The purity of each raw material component alloy powder of the near-nickel layer welding material is ≥99.9%.

[0109] The particle size of the powder for the near-nickel layer welding material is 100 mesh.

[0110] Step 2: place the powder weighed in step 1 in a vacuum heating furnace and heat it, the heating temperature is 222℃, and the holding time is 1.7h, to remove the crystal water in the powder; place the dried powder in a powder mixer for thorough mixing, and the mixing time is 1.7h; Step 3: use pure nickel tape as the welding skin, use alcohol to remove the grease on the surface of the pure nickel tape, wrap the powder prepared in step 2 in the pure nickel tape through the powder core welding wire drawing equipment, and the first drawing die hole diameter is 2.6mm; In step 3, the filling rate of the flux-cored wire is controlled at 24wt%; the thickness of the pure nickel strip is 0.4mm, and the width is 7mm.

[0111] In step 4, after the first process drawing is completed, the hole diameter of the mold is sequentially reduced, and finally the flux-cored wire with a diameter of 1.2mm is obtained.

[0112] In step 5, after the drawing of the flux-cored wire is completed, the flux-cored wire is wound on the welding wire disc through the wire winding machine, and finally sealed in the vacuum packaging bag of the flux-cored wire for use.

[0113] The near-copper layer welding material and the near-nickel layer welding material prepared in Example 5 are used to prepare a copper-nickel gradient structure by low heat input CMT, and the specific steps are as follows (as shown in Figure 1 Step 1: Select the above-mentioned near-copper layer welding material, and use the CMT arc welding process to prepare the near-copper layer on the copper base, the CMT welding current is 255A, and the thickness of the deposited layer is 3.5mm; Step 2: Select the above-mentioned near-nickel layer welding material, and use the CMT arc welding process to prepare the near-nickel layer on the near-copper layer prepared in step 1; the CMT welding current is 165A, and the thickness of the deposited layer is 3.5mm.

[0114] Step 3: Use ERNi-1 pure nickel welding wire to prepare a nickel layer on the near-nickel layer prepared in step 2 by CMT arc welding, the welding current is 185A, and the thickness of the deposited layer is 12.5mm.

[0115] After testing, the tensile strength of the copper-nickel gradient structure is 288MPa.

[0116] Example 6 The specific steps of the preparation method of the near-copper layer welding material are as follows: Step 1: The Ni powder, Zn powder, Si powder, Sn powder and Cu powder are weighed according to the mass percentage of 49.0%, 19.0%, 9.0%, 9.0% and the balance, respectively; the sum of the mass percentages of the above components is 100%. The purity of each raw material component alloy powder of the above-mentioned near-nickel layer welding material is ≥99.9%.

[0117] The particle size of the powder for the near-nickel layer welding material is 100 mesh.

[0118] Step 2: Put the powder weighed in step 1 into a vacuum heating furnace and heat it, the heating temperature is 230℃, and the holding time is 1.9h to remove the crystal water in the powder; after drying, the powder is placed in a powder mixer for thorough mixing, and the mixing time is 1.9h; ​Step 3: using pure copper strip as the welding skin, using alcohol to remove the grease on the surface of the pure copper strip, and wrapping the powder prepared in step 2 in the pure copper strip through the core wire drawing equipment; the first drawing die has a hole diameter of 2.6 mm; In step 3, the filling rate of the core wire is controlled at 30wt%; the thickness of the pure copper strip is 0.4 mm, and the width is 7 mm.

[0119] Step 4: after the first process of drawing is completed, the die hole diameter is sequentially reduced, and finally the core wire with a diameter of 1.2 mm is obtained.

[0120] Step 5: after the core wire drawing is completed, the wire is wound on the wire spool through the winding machine, and finally sealed in the core wire vacuum packaging bag for use.

[0121] The preparation method of the near-nickel layer welding material is as follows: Step 1: Cu powder 49.0%, Ag powder 19.0%, Zn powder 19.0%, and the rest is Ni powder are weighed according to the mass percentage, and the sum of the mass percentages of the above components is 100%; The purity of each raw material component alloy powder of the near-nickel layer welding material is ≥99.9%.

[0122] The particle size of the powder for the near-nickel layer welding material is 100 mesh.

[0123] Step 2: the powder weighed in step 1 is heated in a vacuum heating furnace, the heating temperature is 250℃, the holding time is 1.9h, and the crystal water in the powder is removed; the dried powder is placed in a powder mixer for thorough mixing, and the mixing time is 1.9h; Step 3: using pure nickel strip as the welding skin, using alcohol to remove the grease on the surface of the pure nickel strip, and wrapping the powder prepared in step 2 in the pure nickel strip through the core wire drawing equipment; the first drawing die has a hole diameter of 2.6 mm; In step 3, the filling rate of the core wire is controlled at 25wt%; the thickness of the pure copper strip is 0.4 mm, and the width is 7 mm.

[0124] Step 4: after the first process of drawing is completed, the die hole diameter is sequentially reduced, and finally the core wire with a diameter of 1.2 mm is obtained.

[0125] Step 5: after the core wire drawing is completed, the wire is wound on the wire spool through the winding machine, and finally sealed in the core wire vacuum packaging bag for use.

[0126] The near-copper layer welding material and the near-nickel layer welding material prepared in Example 6 are used to prepare a copper-nickel gradient structure low heat input CMT, and the preparation method of the copper-nickel gradient structure low heat input CMT is as follows (as shown in Figure 1 ​Step 1, selecting the near-copper layer welding material described above, using CMT arc welding process to prepare the near-copper layer on the copper base, the CMT welding current is 290A, the thickness of the deposited layer is 3.9mm; Step 2, selecting the near-nickel layer welding material described above, using CMT arc welding process to prepare the near-nickel layer on the near-copper layer prepared in step 1; the CMT welding current is 190A, the thickness of the deposited layer is 3.9mm.

[0127] Step 3, using ERNi-1 pure nickel welding wire to prepare the nickel layer on the near-nickel layer prepared in step 2 by CMT arc welding, the welding current is 240A, and the thickness of the deposited layer is 14mm.

[0128] Test results show that the tensile strength of the copper-nickel gradient structure is 297MPa.

Claims

1. A welding material for a copper-nickel gradient structure low heat input CMT, characterized by, The near-copper layer welding material and the near-nickel layer welding material are included; The near-copper layer welding material includes powder and a welding sheath, and the powder includes the following components in percentage by mass: 40.0-50.0% of Ni powder, 10.0-20.0% of Zn powder, 5.0-10.0% of Si powder, 5.0-10.0% of Sn powder, and the balance of Cu powder, and the sum of the percentages by mass of the above components is 100%. The near-nickel layer welding material includes powder and a welding sheath, and the powder includes the following components in percentage by mass: 40.0-50.0% of Cu powder, 10.0-20.0% of Ag powder, 10.0-20.0% of Zn powder, and the balance of Ni powder, and the sum of the percentages by mass of the above components is 100%.

2. The welding material for copper-nickel gradient structure low heat input CMT production according to claim 1, characterized in that, The welding sheath of the near-copper layer welding material is a pure copper strip with a thickness of 0.4 mm and a width of 7 mm. The filling rate of the near-copper layer welding material is controlled to be 25-30 wt%.

3. The welding material for copper-nickel gradient structure low heat input CMT production according to claim 1, characterized in that, The welding sheath of the near-nickel layer welding material is a pure nickel strip with a thickness of 0.4 mm and a width of 7 mm. The filling rate of the near-nickel layer welding material is controlled to be 20-25 wt%.

4. The welding material for copper-nickel gradient structure low heat input CMT production according to claim 1, characterized in that, The preparation method of the near-copper layer welding material includes the following steps: Step 1: the powder is weighed according to the percentage by mass, including 40.0-50.0% of Ni powder, 10.0-20.0% of Zn powder, 5.0-10.0% of Si powder, 5.0-10.0% of Sn powder, and the balance of Cu powder, and the sum of the percentages by mass of the above components is 100%. Step 2: the powder weighed in step 1 is heated in a vacuum heating furnace at a temperature of 200-240 ℃ for 1-2 h, and then the dried powder is placed in a powder mixer for fully mixing for 1-2 h. Step 3: a pure copper strip is used as the welding sheath, alcohol is used to remove grease on the surface of the pure copper strip, the powder prepared in step 2 is wrapped in the pure copper strip through a flux-cored wire drawing equipment, and the first drawing die has a hole diameter of 2.6 mm. In step 3, the filling rate of the flux-cored wire is controlled to be 25-30 wt%, the thickness of the pure copper strip is 0.4 mm, and the width is 7 mm. Step 4: after the first drawing process is completed, the hole diameter of the die is gradually reduced, and finally a flux-cored wire with a diameter of 1.2 mm is obtained. Step 5: after the drawing of the flux-cored wire is completed, the flux-cored wire is wound on a wire spool through a wire winding machine, and finally sealed in a vacuum packaging bag for use.

5. The welding material for copper-nickel gradient structure low heat input CMT production according to claim 1, characterized in that, The preparation method of the near-nickel layer welding material includes the following steps: Step 1: the powder is weighed according to the percentage by mass, including 40.0-50.0% of Cu powder, 10.0-20.0% of Ag powder, 10.0-20.0% of Zn powder, and the balance of Ni powder, and the sum of the percentages by mass of the above components is 100%. Step 2: the powder weighed in step 1 is heated in a vacuum heating furnace at a temperature of 220-260 ℃ for 1-2 h, and then the dried powder is placed in a powder mixer for fully mixing for 1-2 h. Step 3: using pure nickel strip as the solder, using alcohol to remove the grease on the surface of the pure nickel strip, and wrapping the powder prepared in step 2 in the pure nickel strip through the core wire drawing equipment; the first drawing die has a hole diameter of 2.6 mm; In step 3, the filling rate of the flux-cored wire is controlled at 20wt%-25wt%; the thickness of the pure nickel strip is 0.4 mm, and the width is 7 mm; Step 4: after the first process of drawing is completed, the die hole diameter is sequentially reduced, and finally a flux-cored wire with a diameter of 1.2 mm is obtained; Step 5: after the drawing of the flux-cored wire is completed, the wire is wound on the wire spool by a winding machine, and finally sealed in a vacuum packaging bag for use.

6. A method for low heat input CMT manufacturing of copper-nickel gradient structures, characterized in that, The specific steps are as follows: Step 1, selecting the near-copper layer welding material according to claim 1, and using CMT arc welding process to prepare the near-copper layer on the copper base; Step 2, selecting the near-nickel layer welding material according to claim 1, and using CMT arc welding process to prepare the near-nickel layer on the near-copper layer prepared in step 1; Step 3, using ERNi-1 pure nickel welding wire to prepare a nickel layer on the near-nickel layer prepared in step 2 by CMT arc welding.

7. The low heat input CMT method of claim 6, wherein the copper-nickel gradient structure is formed by the low heat input CMT method. In step 1, the CMT welding current is 250A-300A, and the thickness of the deposited layer is 2mm-4mm; In step 2, the CMT welding current is 160A-200A, and the thickness of the deposited layer is 2mm-4mm; In step 3, the CMT welding current is 180-250A, and the thickness of the deposited layer is 10mm-15mm.

8. A copper-nickel gradient structure, characterized by Prepared by the method of claim 6.

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